The invention relates to a multilayer body and to a method for the production thereof.
Multilayer bodies as a security element can be taken as known from the state of the art and are widely used to protect bank notes, securities and identity documents against forgery or for the authentication of products. They are based on a combination of several functional layers, which may, for example, comprise optically variable elements (OVD=Optical Variable Devices), diffractive elements, partially metalized layers or printed features.
It is known to produce such multilayer bodies by the sequential application of individual layers, building up the desired layer sequence. In order to obtain multilayer bodies that are particularly secure against forgery, it is desirable to allow features of the individual layers to transition seamlessly into each other. In other words, the layers should be arranged as accurately as possible in register with each other.
By register or register accuracy is meant the accurately positioned arrangement of layers which are superimposed or lying next to each other relative to each other, maintaining a desired positional tolerance. The term “register” originates from the register marks or also control marks being used, by means of which the positional tolerance can be measured and monitored.
Where the multilayer body is built up sequentially, however, this cannot always be achieved since the methods used to produce each individual layer are subject to tolerances in terms of the position of the layers relative to each other. As a result, the desired seamless transitions between the features cannot be achieved reliably, which has a negative effect on the security against forgery and the optical appearance of such a multilayer body.
This applies in particular when different layers are to be arranged in each case in register with each other in different areas of the multilayer body.